Firing mechanism for firearms

ABSTRACT

An automatically selective firing mechanism for use in a doublebarrelled firearm of the type having a single trigger. The system contains a double sear, double hammer firing arrangement. The firing mechanism automatically arms the unfired sear after the first sear has dropped. This secondary arming takes place by releasing the trigger. The mechanism is free of any tendency toward accidental double firing, often referred to as &#39;&#39;&#39;&#39;doubling.&#39;&#39;&#39;&#39; This is accomplished without the use of separate mechanical restraining mechanisms or inertial weights. This invention is so constructed that a sudden jarring shock, such as that experienced in the dropping of the firearm, will not tend to discharge the gun. In addition, the sears and hammers are arranged to provide an extremely fast lock time. Selection of the barrel to be fired, and the release of the safety is accomplished in one easy flip of the selector lever. The lever is so positioned upon the top tang of the firearm to afford ease and comfort of barrel selection to both right and left-handed shooters.

United States Patent [191 Linde FIRING MECHANISM FOR FIREARMS [75] Inventor: John P. Linde, llion, NY.

[73] Assignee: Remington Arms Company, Inc.,

Bridgeport, Conn.

22 Filed: Feb. 2, 1973 21 Appl. No.: 329,218

Related US. Application Data [63] Continuation-impart of Ser. No. 148,825, June l,

1971, abandoned.

[52] US. Cl 42/42 R [5]] Int. Cl. F4lc 19/00 [58] Field of Search 42/42 R [56] References Cited UNITED STATES PATENTS 2,203,378 6/1940 Browning 42/42 R 2,295,941 9/1942 3,444,640 5/1969 Simmons 42/42 R Primary Examiner-Benjamin A. Borchelt Assistant ExaminerC. T. Jordan Attorney, Agent, or Firm-John H. Lewis, Jr.; Nicholas Skovran; Joel D. Talcott Jilin I V [451 May 7,1974

[5 7] ABSTRACT An automatically selective firing mechanism for use in a double-barrelled firearm of the type having a single trigger. The system contains a double sear, double hammer firing arrangement.

The firing mechanism automatically arms the unfired sear after the first sear has dropped. This secondary arming takes place by releasing the trigger. The mechanism is free of any tendency toward accidental double firing, often referred to as doubling. This is accomplished without the use of separate mechanical restraining mechanisms or inertial weights.

This invention is so constructed that a sudden jarring shock, such as that experienced in the dropping of the firearm, will not tend to discharge the gun.

In addition, the sears and hammers are arranged to provide an extremely fast lock time.

Selection of the barrel to be fired, and the release of the safety is accomplished in one easy flip of the selector lever. The lever is so positioned upon the top tang of the firearm to afford ease and comfort of barrel selection to both right and left-handed shooters.

10 Claims, 8 Drawing Figures minimum 1 m4 $808724 SHEET 1 [IF 4 1 FIRING MECHANISM FOR FIREARMS This application is a continuation-impart of copending application Ser. No. 148,825, filed on June 1, 1971, now abandoned.

The present invention relates to an automatically selective firing mechanism for double-barrelled firearms having a single trigger, and more particularly to a system of this type comprising a double sear, double hammer arrangement.

Heretofore, automatically selective firing mechanisms designed for single trigger, double-barrelled firearms were plagued with many reliability problems. Many times a shooter would be inclined to involuntarily pull the trigger a second time after firing the first barrel. This unintended double-firing is commonly known as doubling. It is usually caused by an involuntary reaction that is further exacerbated by inertial forces of one kind or another generated in recoil and/or counter-recoil. To correct for this problem, firing systems were devised of the kind shown to V. A. Browning, U. S. Pat. No. 3,421,243, issued Jan. 14, 1969. Systems of this type use an inertial mass to restrain the connector arm-of the trigger assembly from contacting the second unfired .sear. Generally, these systems are designed to prevent arming the second sear until after the recoil forces are dissipated, thus preventing doubling." In many such systems, failure to initiate the first round prevents selection of the second barrel.

The most serious drawback of inertia-mass operation, however, is caused by the different ways shooters have in gripping the gun to their shoulders. The result is that the working characteristics of the inertial mass will vary with the individual. In other words, the inertial force experienced by this mass varies as a function of the force exerted in placing the firearm into the humeral cavity. A loosely gripped firearm would often result in there being insufficient inertial force acting upon the connector arm of the system.

The present system does away with the separate inertia weight of the aforementioned systems. In addition, it does not rely upon springs or other mechanical means to restrain the connector arm from engaging the sears in recoil or counter-recoilas in the system of the type shown in the U. S. patent to H. E. Heiter, issued Oct. 25, 1966, U.S. Pat. No. 3,280,494.

This invention relies upon the mechanical positioning of its firing linkage and the inertial forces of the parts themselves to provide the necessary reliability.

Briefly, after initial selection is accomplished, the connector arm of the present firing mechanism is forced downward upon the selected sear by the pulling of the trigger. As the sear-engageable shoulder of the connector arm attempts to move upward to engage with the upper surface of the unfired sear, it is prevented from doing so by an inclined surfaceon the end face of the unfired sear which holds the shoulder down. The connector arm remains engaged upon this lower inclined surface through recoil by way of the inertial force imposed upon the connector arm. When counterrecoil takes place, the connector arm is thrown rearward by the counter-recoil inertial force, so that it once again remains out'of contact with the unfired sear.

Thus, the present system uses less parts to prevent doubling than either the previous mechanical or inertial firing mechanisms.

It was, therefore, a primary object of this invention to design an automatically selective firing mechanism of the non-doubling" type for use in single trigger, double-barrelled firearms which has less parts.

It was another primary object of this invention to provide an automatically selective firing mechanism for single trigger, double-barrelled firearms which was devoid of any tendencies to discharge the firearm upon sudden shocking of the system, as occurs in the case when the gun is dropped.

It was but another primary object of this invention to provide an automatically selective firing mechanism having a selector lever operative to both select the first barrel to be fired and to unsafe the firearm in one easy step.

It is still another object of this invention to provide a firing mechanism for single trigger, double-barrelled firearms which has an extremely rapid lock time.

Another object of this invention; is to provide a firing mechanism for single trigger, double-barrelled firearms which is both safe, accurate, and reliable.

Still another object of this invention is to provide an automatically selective firing mechanism having a selector lever which is designed for both ease and comfort in selecting the first barrel to be fired, and which is convenient for both right and left-handed shooters.

It is a further object of this invention to provide a firing mechanism for single trigger, double-barrelled firearms which will automatically select the other barrel to be fired after initial firing of the first barrel, irrespective of whether or not the initial barrel was discharged.

It is but a further object of this invention to provide a firing mechanism for a single trigger, doublebarrelled firearm having a selector lever which also functions as an indicator to visibly point to the barrel so selected.

It is another object of this invention to provide a firing mechanism having a trigger assembly of a unique four-bar linkage construction.

These and other objects of this invention will present themselves and will be more readily understood and defined with reference to the following detailed description and conjoining drawings in which:

FIG. 1 is a side view of the firing mechanism of this invention;

FIG. 2 is an isometric side view of the firing mechanism of this invention with the selector lever in the neutral or safe position;

FIG. 3 is an isometric side view of the firing mechanism of this invention with the selector lever positioned for the firing of the top barrel;

FIG. 4 is an isometric side view of the firing mechanism of this invention with the selector lever positioned for the firing of the bottom barrel;

FIG. 5 is a top view of the selector lever and top tang section of the receiver;

FIG. 6 is an isometric frontal view of a portion of the firing mechanism of this invention subsequent to the firing of the bottom barrel;

FIG. 7 is a side elevational view of the connector arm mounting means showing the extent of lateral movement in dotted lines; and

FIG. 8 is an enlarged view of the bottom end of the connector arm showing the construction which permits lateral movement of the connector arm.

Generally speaking, the subject invention is for an automatically selective, single trigger firing mechanism for a double-barrelled firearm. The firing system does not rely upon an inertia-mass nor mechanical restraints to prevent doubling. The firing of the second barrel can only be accomplished after the trigger has been pulled to fire the first barrel and has returned to its rest position and after recoil and counter-recoil cycles have terminated. Thus, the additional release and squeezing of the trigger while in the pulled position will not cause the other barrel to fire.

The mechanism comprises a receiver housing with a breech end. A pair of hammers are located side-by-side in the housing and are pivotally mounted and biased for forward movement. A pair of closely adjacent sears engage the hammers against forward movement. The sears are biased into positive engagement with their respective hammers.

A forwardly biased trigger is provided which operates from a rest position to a pulled position. The trigger has an upper elongated base having a forward end and a rearward end. The trigger is pivotable about the receiver between the ends of the base. An elongated upstanding connector arm is articutatively attached to the forward end of the trigger base at one end, and is engageable at its other end with either one of the sears at their rearward end. The connector arm comprises a first sear-engageable step at its sear-engageable end. To the rear on either side of the first step is a second searengageable step. Selector means is provided for positioning the first step of the connector arm upon either of the two sears when both hammers are cocked. Biasing means is attached to the connector arm to urge the connector arm into engaging the selected sear upon its first step and subsequent to that, a pivoting of the engaged sear will cause the connector to move further forward to engage the other sear upon its second step after the trigger fully returns from its pulled to its rest position, and after recoil and counter-recoil cycles have terminated.

Now referring to FIG. 1, a side view of the firing mechanism of this invention is shown. A receiver 1 is provided to house the mechanism. A selector lever 2 is mounted upon the top tang 1a of the receiver housing as depicted. The selector lever 2 pivots about its forward end so that its selective end 45 moves in an arcuate path from a first position to a second position as shown by arrows 60 in FIG. 5. If the selector end 45 of the lever is moved in an arcuate manner clockwise as depicted by arrow 75 in FIG. 4, the bottom barrel will be selected to fire. If the selector end 45 is thumbed counter-clockwise as illustrated by arrow 70 in FIG. 3, the top barrel will be selected.

Selection is accomplished by placing tab 21 of the connector arm 22 upon steps 25 and 25' respectively of either of the two sears 8 and 8'. The sears 8 and 8' respectively engage the hammers 5 and 5', as shown in FIGS. 3 and 4. The sears are pivotally mounted within sear housing 6 and pivot about pin 7. Each sear is biased downwardly by means of coil springs 63 so as to positively engage its respective hammer at point 50, and hold it in the cocked position (see FIG. 1). The hammers 5 and 5 are respectively pivotable about pivot points 26 and 26, for forward movement toward the firing pins (not shown), disposed in housing 51.

The connector arm 22 is moved laterally within the housing with the arcuate movement of selector lever 2 from the clockwise to the counter-clockwise position and vice versa. In so moving, the connector arm aligns tab 21 with either of the two steps 25 and 25'. A spring 29 urges the connector arm 22 forward so that tab 21 comes into positive contact with one of the steps as shown in FIGS. 3 and 4.

As explained above, it is necessary in the present design that connector arms 22 and 27 have a predetermined amount of lateral movement so that the tab 21 can be moved laterally to engage one or the other of the sears. The structure permitting this lateral movement of arm 22 is the same as arm 27 so that an explanation of one, i. e. connector arm 22, should suffice to explain the connection of arm 27 as well.

As can best be seen in FIGS. 2-4, the lower end of connector arm 22 is positioned in slot 62 of the trigger base 33. From FIGS. 7 and 8 it can be seen that the lower end portion 22a of the connector arm is substantially enlarged and radiused on either side so that the maximum thickness X of the enlarged portion 220 is just slightly less than the width of slot 62. These radii are such that when the forward connector and rear connector arms rotate or move from side to side (as shown in FIG. 7), so that the forward connector can engage the desired sear, the radiused ends pivot in the slot so as to offer a constant part thickness to the corresponding slots in the trigger base. By using the radii on the sides of the forward connector and rear connector, the lateral rotation is possible with very little slop or side-to-side play of the connector bars in the trigger slots.

FIG. 8 shows an enlarged view of the lower end portion 22a. It can be seen that an opening 320 is provided in the lower end of arm 22 by which the arm is pivotally mounted on pin 32. Opening 32a comprises a central bearing portion 32b and counterbored or bevelled portions 320 on each side of the central bearing portion. It will be understood that the counterbored portions 32c, as shown in dotted lines in FIG. 8, reduce the clearances necessary for the connector arms to rotate laterally with the specific limits. On a trigger connector pivot, the loads or forces are very low, therefore a minimum of bearing area is needed for a safe and reliable pivot. The lateral angles necessary are very slight and with a minimum of clearance between the pivot pin and the counterbored pivot holes, the system works very well with no perceptible play on the trigger linkage.

The arcuate motion of lever 2 is translated into lateral motion for the connector arm 22 by means of toggle block 9, shaft 17, and selector block 18 as follows:

Toggle block 9 is rigidly connected to shaft 3. Since the lever 2 is also rigidly connected to shaft 3, the toggle block will have the same prescribed motion as that of the selector lever. From the center of toggle block 9, extending downward, is shaft 17 having a sphericalshaped tip. The tip rides within the prolongated slot 28 within selector block 18.

When the selector lever 2 is thumbed clockwise as illustrated in FIG. 4 by arrow 75, the toggle block 9 also pivots clockwise, causing shaft 17 to move the selector block 18 laterally in the direction of arrow 95. Since the connector arm 22 is joined to selector block 18 by pin 34, it too will move in the direction of arrow 95, thus aligning tab 21 opposite step 25 of sear 8.

When the selector lever 2 is thrust counterclockwise as depicted by arrow of FIG. 3, the selector block will be forced by shaft 17 in the direction shown by arrow 90. Tab 21 will now align itself opposite step 25 of sear 8. The connector arm 22 is pivotal forward about trigger base 33 through pin 32 in order to contact the sears. It also pivots laterally a small distance to either side within slot 62 of trigger base 33 so that tab 21 can be directed opposite the respective hammerreleasable ends 25 and 25 of sears 8 and 8.

In addition to the two arming positions, the selector lever has a neutral or safe position as illustrated in FIGS. 2 and 5. When the lever 2 is in the neutral position, the selector block 18 is cammed backward so that the connector arm 22 cannot contact the sears. This is accomplished by means of the toggle link which pivots from the tail-end of toggle block 9 about pivot pin 14. Pin 11 extends from the rearward end of toggle link 10 and engages with abutment face 43 of selector block 18, when the selector lever approaches the neutral position. When the selector lever is put on safe, the pin 11 contacts abutment face 43 and forces the selector block backward to disengage the connector tab 21 from the sears. As the selector lever is flipped to either of its selective positions, the pin 11 moves forward, away from the selector block 18, allowing it to come forward and thus permit the connector tab 21 to engage the seats. Toggle link 10 arcs in the opposite direction to the movement of the selector lever. This occurs as a result of pin 12 which is actually an upward extension of pin 11. Pin 12 extends into slot 16 of the receiver, and has a slide block at its upper end. Slide block 15 slides forwardly and backwardly in slot 16,

causing the rearward end of the toggle link 10 to do the 1 same. This restraint upon the rearward portion of the toggle link forces the link to pivot about pivot pin 14 in the opposite sense to the toggle block 9 and selector lever 2 as shown in FIGS. 3 and 4. Thus, as the link 10 moves clockwise (arrow 80 in FIG. 3), the toggle block 9 is moving counter-clockwise (arrow 70), and as the link 10 moves counter-clockwise (arrow 95 in FIG. 4), the toggle block 9 is moving clockwise (arrow 75).

The lower section of the firing mechanism is designed as a four-bar linkage comprising the trigger base 33 with the upstanding connector arm 22 hinged at its forward end at pivot point 32, and upstanding arm 27 hinged at its rearward end at pivot point 30. The selector block 18 completes the fourth link by hinging to the connector arm 22 at pivot point 34, and the connector arm 27 at pivot point 31. This section was designed as a four-bar linkage to counter-balance the firing mechanism to produce a system that could be shock-loaded. In other words, the gun can be dropped or mishandled with the selector lever off the safe position, without discharging the firearm. It should be noted that arm 27 has a radiused enlarged lower end which pivots laterally in slot 61 of the trigger base 33, as explained with connector arm 22 above, so that the entire linkage pivots laterally. Trigger 4 is pivotally mounted on the lower tang lb of receiver 1 about pin to activate the linkage.

Spring is made very strong to provide a quick hammer drop (lock time).

Spring 29 not only urges connector arm 22 forward to engage the sears, as aforementioned, but also serves to bias the trigger 4 forward so that it will return to its initial forward at-rest position from the rear pulled position. This is one way the present system reduces the number of parts required.

The dual function of spring 29 can be explained as follows: Spring 29 is a double-acting torsion spring having its central coiled portion mounted on pivot pin 32, which is rigidly mounted on the forward end of trigger base 33 (see FIG. 2). Trigger base 33, in turn, has an opening 35a through which pin 35 is inserted to pivot the base 33 to the lower tang lb of the receiver. Spring 29 also includes integrally-formed upper and lower spring arms 29a and 29b respectively.

It can be seen that when the ends of spring arms 29a and 29b are moved toward each other, the spring is stressed and the spring arms 29a and 29b will have a tendency to move away from each other, i. e. spring arm 29a will want to move clockwise about pivot 32 and spring arm 29b will want to move counterclockwise about pivot 32. If lower spring arm 29b is restrained against movement by abutting against the lower tang 1b of the receiver (as shown in'FIG. 1), the result will be that upper arm 29a will be biased forwardly against connector arm 22 thus biasing arm 22 forwardly. At the same time, because the end of lower spring arm 29b wants to move downwardly and is restrained from doing so, the result is that pivot 32 and the connected forward end of trigger base 33 is moved thus causing trigger 4 to be biased forwardly.

There are three circular depressions, 46, 47, and 48,

respectively, in the rearward end of the toggle block 9. A spring-loaded detent ball 52 (FIG. 1) engages these holes to provide a snap-action effect when the lever is thumbed to its various positions. FIG. 5 shows the top tang of the firearm with the three positions: B, N," and T, respectively, designating the bottom barrel firing position, the safe or neutral position, and the top barrel position.

FIG. 6 depicts the connector portion of the firing mechanism after one of the sears has been released. The connector arm 22 has a forward tab 21 for initially engaging steps 25 or 25', respectively. In FIG. 6, the tab 21 initially engaged step 25. When the trigger 4 was pulled, connector arm 22 moved downward to depress sear 8' into releasing its hammer 5. The hammers each have a camming surface extending backward from the point of sear engagement to the end of the hammer profile as shown by 23. As the sear 8' pivots to release hammer 5, it pivots still further as the hammer drops due to the camming action of surface 23 upon the forward end of the sear. Thus, the step 25 is depressed out of the way of any further contact with the connector arm. When the trigger 4 is released from the pulled position, and allowed to fully return to its at-rest position, the connector arm 22 moves upward and f0rward to engage the remaining sear 8. If seat 8 has been initially selected, the connector arm would have then contacted sear 8' which would have been the remaining sear. The second respective sear engagement is made by either steps 20 or 20' as the case may be. Step 20 and 20 are lumps or shoulders which are respectively located to the rear of tab 21 and on either side thereof. Thus, when tab 21 aligns itself with the searengageable step 25, lump 20' is in line with searengageable step 25'. After step 25 is depressed, and sear 8 is cammed out of the way, lump 20 will come to rest upon step 25 of sear 8' if the trigger is released. Conversely, if tab 21 initially aligns itself for engagement with step 25, lump 20 will be in line with step 25,

and will engage it after the trigger is pulled and released.

The firing system is thus automatically selective. Because the mechanism requires that the trigger be released before the connector arm will engage with the remaining sear, there is little chance of experiencing the doubling condition. In addition, doubling is prevented during the troublesome recoil or counter-recoil cycles even if the trigger is released and pulled a second time.

After initial selection has occurred, a pull of the trigger 4 will cause the connector arm 22 to move downward, causing tab 21 to move downward upon the selected sear step 25 or 25, as the case may be. Each sear 8 and 8, respectively, has an inclined surface 49 on its end face, as shown in FIGS. 1-4 and 6. The connector arm 22 will try to move upward when trigger 4 is released, under the action of spring 29. However, the connector step or 20, as the case may be, will remain engaged with the end face inclined surface 49 of the sear, and is prevented from moving upward to engage with the upper step 25 or 25 of the sear. This contact is maintained during recoil because of the inertial force created upon the connector arm 22. In other words, the connector arm 22 will be forced forward upon this lower inclined surface 49 of the sear by the inertia of ITS OWN MASS. The connector step 20 or 20' will not be able to slide off the lower inclined surface 49 of the sear during recoil. This is not only due to the forward inertial force of the connector arm 22 but also to the inclined geometry of surface 49, which makes it additionally difficult for the connector step to move upward. It should be noted that the forces in recoil greatly outweigh the restoring force exerted by spring 29 upon the connector arm 22.

During counter-recoil, the shoulder 20 or 20, respectively, is again prevented from engaging the shoulder 25 or 25 of the sear, since the inertia force upon connector arm 22 is now acting backward. Thus, the connector arm is forced backward out of reach of the scars until the counter-recoil cycle is ended. Because the system accomplishes its objectives without the use of inertia weights or mechanical restraining devices, it can be said to be functionally more positive. The firing mechanism of this invention is neither purely mechanical nor purely inertial in its design. Thus, the system can be considered as a hybrid mechanism.

As will be obvious to those skilled in the art, an inertia weight may be added to the system to further enhance the inertial effects. However, this would add nothing in the way of function to the system, as it will adequately operate without any additional mass.

Modifications and changes of this character, which would be obvious to the skilled practitioner, are considered to be within the purview and scope of this invention as represented by the appended claims.

What is claimed is:

1. An automatically-selective single-trigger firing mechanism for a double-barrelled firearm, comprising:

a receiver housing with a breech end;

a pair of hammers disposed side-by-side in said housing and pivotally mounted for forward movement toward said breech end;

biasing means urging each hammer forwardly;

a pair of sears, each having a forward hammerengageable end and a rear connector arm engageable end, said sears pivotally mounted closely adjacent each other within said receiver housing;

biasing means urging each sear into engaging its respective hammer in a cocked position against forward movement until the sear pivots to release it;

a trigger means pivotally mounted to said receiver housing so as to be operative between a forward rest position and a rear pulled position;

biasing means urging the trigger means forwardly to the rest position;

an upstanding connector arm, means articulatively connecting the lower ends of said connector arm to said trigger means so as to permit the connector arm to pivot on a horizontal axis as well as to move laterally a predetermined distance, said connector arm having at its upper end a first sear-engageable step and to the rear on either side of said step, a second sear-engageable step;

selector means to move the connector arm laterally to position the first step of the connector arm either upon one of said sears when both hammers are cocked, whereupon the appropriate second step of the connector arm will be lined up with the other sear or upon neither of the sears whereupon the firearm is in a safe, non-firing condition;

mechanical biasing means for urging the connector arm forward to engage the selected sear upon its first step so that upon pulling the trigger means, the connector arm is lowered to force the selected sear down to release the engaged hammer and to permit said connector arm to move further forward to have said second sear engaging step engage the other sear after the trigger means fully returns from its pulled to its rest position, and after recoil and counter-recoil cycles have terminated.

2. The automatically selective firing mechanism of claim 1 further characterized in that each of said hammers has a camming surface on its upper peripheral edge thereof, extending from the point of sear engagement a limited distance along said peripheral edge, whereby the forward movement of the hammers will cam their respective sears into pivoting beyond their hammer-releasable position and prevent the sears from engaging with the connector arm until the hammers have been re-cocked.

3. The automatically selective firing mechanism of claim 1, further characterized in that each respective sear has an inclined surface on its rearward end face, whereby the sear in the hammer-engaged position will prevent the second step of the connector arm from moving upward during recoil to engage with its hammer releasable end.

4. An automatically-selective single-trigger firing mechanism for a double-barrelled firearm, comprising:

a receiver with a breech end;

a pair of hammers disposed side-by-side in said receiver and pivotally mounted for forward movement toward said breech end;

biasing means urging each hammer into forward movement;

a pair of elongated sears each having a forward hammer-engageable end and a hammer releasable end, said sears pivotally mounted closely adjacent each other within the receiver;

9 biasing means urging each sear into engaging its respective hammer in a cocked position against forward movement until the sear pivots to release it; a trigger operative between a pulled and rest position having an upper elongated base comprising a forward end and a rearward end, said trigger pivotally mounted to said receiver between the ends of the base;

biasing means to urge the trigger towards the rest position from said pulled position;

an elongated upstanding connector arm articulatively attached at one end thereof to the forward end of said trigger base, and engageable at the other end thereof with the rearward end of either of the two sears when said hammers are in the cocked position; said connector arm further comprising a first sear engageable step at its sear-engageable end, and to the rear on either side of said first step, a second sear-engageable step;

selector means for positioning the first step of the connector arm upon either one of said sears when both hammers are cocked;

mechanical biasing means for urging the connector arm forward to engage the selected sear upon its first step and subsequent to that, a pivoting of the engaged sear will cause said connector arm to move further forward to engage the other sear upon said second step after the trigger fully returns from its pulled to its rest position, and after recoil and counter-recoil cycles have terminated;

a second elongated upstanding connector arm articulatively attached at its lower end thereof to the rearward end of said trigger base; and

an elongated selector block positioned above the trigger base and pivotally connected to the forward connector arm at its sear engageable end, and the second connector arm to form a four-bar linkage assembly.

5. An automatically-selective single-trigger firing mechanism for a double-barrelled firearm comprising:

a receiver housing with a breech end;

a pair of hammers disposed side-by-side in said housing and pivotally mounted for forward movement toward said breech end;

biasing means urging each hammer into forward movement;

a pair of elongated sears each having a forward hammer-engageable end and a hammer releasable end, said sears pivotally mounted closely adjacent each other within the receiver housing;

biasing means urging each sear into engaging its respective hammer in a cocked position against forward movement until the sear pivots to release it;

a trigger operative between a pulled and rest position having an upper elongated base comprising a forward end and a rearward end, said trigger pivotally mounted to said receiver housing between the ends of the base;

biasing means to urge the trigger towards the rest position from said pulled position;

an elongated upstanding connector arm articulatively attached at one end thereof to the forward end of said trigger base, and engageable at the other end thereof with the rearward end of either of the two sears when said hammers are in the cocked position; said connector arm further comprising a first sear engageable step at its sear-engageable end, and to the rear on either side of said first step, a second sear-engageable step;

selector means for positioning the first step of the connector arm upon either one of said sears when both hammers are cocked;

mechanical biasing means for urging the connector arm forward to engage the selected sear upon its first step and subsequent to that, a pivoting of the engaged sear will cause said connector arm to move further forward to engage the other sear upon said second step after the trigger fully returns from its pulled to its rest position, and after recoil and counter-recoil cycles have terminated;

said selector means to position the first step of the connector arm upon one of the sears comprising:

a selector lever pivotally connected at a forward end thereof to the receiver housing, with a rearward end pivotably arcuate about said forward end from a first selective position to a second selective position, and having a neutral position between said selective positions; and i a toggle mechanism connected to the selector lever and the connector arm, and operatively constructed to transform the arcuate movement of the selector lever into laterally movingthe connector arm to a position capable of engaging the respective sears.

6. The automatically selective firing mechanism of claim 5, wherein the toggle mechanism comprises:

a toggle block disposed within the housing and rigidly connected at a forward end thereof to the forward end of said selector lever, said toggle block having a rearward end free to pivot about its forward end, whereby the toggle block motion will substantially conform to the motion prescribed to said lever;

an elongated selector block having a prolongated slot and an abutment for engagement with a toggle stud, said selector block attached to the connector arm and restrained to move with said connector arm within the housing; and

an elongated toggle link pivotally attached at one end thereof to the free pivoting end of said toggle block, and having its other end restrained for sliding forward and backward within the receiver housing by a toggle stud extending upwardly into a slot in the wall of the receiver housing, said stud also extending downwardly from said slide to engage the selector block abutment against forward movement when the selector lever is in the neutral position so as to prevent the connector arm from engaging the respective sears.

7. The automatically selective firing mechanism of claim 6, wherein the toggle mechanism further comprises:

a toggle guidepin attached to said toggle block between its forward and rearward ends and extending downwardly from said toggle block to protrude into the prolongated slot of the selector block, whereby the arcuate movement of the selector lever to either its first or second position will cause the toggle guide pin to move laterally within the receiver housing and force the selector block to move to a position capable of engaging the respective sears.

a trigger on said linkage system so that upon pulling mechanism for a double-barrelled firearm comprising:

a receiver housing;

a pair of hammers pivotally mounted in said housing to move from a rear, cocked position to a forward, uncocked position;

biasing means urging each of said hammers forwardly;

a pair of sears pivotally mounted rearwardly of said hammers, each of which selectively engages and retains a corresponding hammer in the cocked position;

a four-bar linkage system positioned rearwardly of said pair of sears, and means pivotally mounting said linkage system to said receiver housing so as to be movable forwardly and rearwardly as well as laterally thereof;

sear engaging means on said linkage system for selectively engaging a predetermined one of said pair of sears, and after firing of the first barrel, to automatically engage the other of said pair of sears;

biasing means urging said linkage system forwardly into sear engaging position;

selector means on said receiver housing connected to said linkage system for laterally moving said linkage system and the'sear engaging means thereon to selectively position the sear engaging means on to the desired sear; and

said trigger rearwardly, the linkage system is caused to be pivoted forwardly and downwardly to depress the selected scar and release the corresponding hammer, thus permitting the firearm to fire.

9. An automatically-selective single-trigger firing mechanism as recited in claim 8 wherein said four-bar linkage system comprises an elongated trigger base, upstanding forward and rear connector arms having their lower ends articuiatively connected to the forward and rear ends respectively of said elongated trigger base, and an elongated selector block positioned above said trigger base and pivotally connected to the upper ends of said forward and rear connector arms respectively.

10. An automatically-selective single trigger firing mechanism for a double-barrelled firearm as recited in claim 9 wherein slot means are provided in 'said trigger base in order to receive the lower ends of said forward and rear connector arms, each of said lower ends of said connector arms having an enlarged and radiused portion with a maximum thickness which is slightly less than the width of said slot means, an opening through each of said enlarged portions through which pivot pins are inserted to mount said connector arms to said trigger base, said openings being angularly relieved at each end of said openings to permit lateral movement of said connector arms relative to said pivot pins.

WWW STATES PATENT 0mm ERTEFIQATE (IQHRECTKUN mmm m 3,808,724 med my 7, 1974 Ta wan-36 1 JOHN P.a LINDE M EU; is martified that error appears in the above idmtified patent @353 mid; Let-mars fi m-mm; nezeb'y curm'mtaci as sham: balmy;

C01 2 Line 33 "was" should read --has Col, Line 42 "specific" should read -'specified.-. Col; 5, Line 10 '"arrmf 95" a'ahraulcl read --ar1 w 85-h C01; 6, Line '54 "has" should read hada, I

Sigragd and 'sealed this 22nd day of October 1974.

(SEAL) Attest:

MfiCUY 1m GIBSON IR. c. MARSHALL DANN Attesting offic r fiommissioner .of Patents gg- STATESfiTENTOFFICE 1 QE QAT 0F (JORRECTIGN maemwo; 3,808,724" (D-107AY j Dated MAY 7, 1974 i t JOHN P," LINDE 1?: is certified fthat error appeafs in the jabove-idefitified pateht am? thatsaid Letters; Patent are-'heieby cbrrecta g2; shawflheinw;

-Co1 QQiLiiae 33 "was" should read -has-. (301.4, Line 42 "specific" should re-aui-*spec;i-fie;3l-- Cpl; 5, Line 40 fi-"ar w 95" should read 'arr'ow 85---. C91; 6, Line '54 "has" should read --h ad- Y Y Signed an d sealed this 22hd day of October 1974.-

( EAL? Attest: I

McCOY M, GIBSON JR. I c. MARSHALL DANN v Attesting Officex 1 Cammissioner .of Patents 

1. An automatically-selective single-trigger firing mechanism for a double-barrelled firearm, comprising: a receiver housing with a breech end; a pair of hammers disposed side-by-side in said housing and pivotally mounted for forward movement toward said breech end; biasing means urging each hammer forwardly; a pair of sears, each having a forward hammer-engageable end and a rear connector arm-engageable end, said sears pivotally mounted closely adjacent each other within said receiver housing; biasing means urging each sear into engaging its respective hammer in a cocked position against forward movement until the sear pivots to release it; a trigger means pivotally mounted to said receiver housing so as to be operative between a forward rest position and a rear pulled position; biasing means urging the trigger means forwardly to the rest position; an upstanding connector arm, means articulatively connecting the lower ends of said connector arm to said trigger means so as to permit the connector arm to pivot on a horizontal axis as well as to move laterally a predetermined distance, said connector arm having at its upper end a first sear-engageable step and to the rear on either side of said step, a second sear-engageable step; selector means to move the connector arm laterally to position the first step of the connector arm either upon one of said sears when both hammers are cocked, whereupon the appropriate second step of the connector arm will be lined up with the other sear or upon neither of the sears whereupon the firearm is in a safe, non-firing condition; mechanical biasing means for urging the connector arm forward to engage the selected sear upon its first step so that upon pulling the trigger means, the connector arm is lowered to force the selected sear down to release the engaged hammer and to permit said connector arm to move further forward to have said second sear engaging step engage the other sear after the trigger means fully returns from its pulled to its rest position, and after recoil and counter-recoil cycles have terminated.
 2. The automatically selective firing mechanism of claim 1 further characterized in that each of said hammers has a camming surface on its upper peripheral edge thereof, extending from the point oF sear engagement a limited distance along said peripheral edge, whereby the forward movement of the hammers will cam their respective sears into pivoting beyond their hammer-releasable position and prevent the sears from engaging with the connector arm until the hammers have been re-cocked.
 3. The automatically selective firing mechanism of claim 1, further characterized in that each respective sear has an inclined surface on its rearward end face, whereby the sear in the hammer-engaged position will prevent the second step of the connector arm from moving upward during recoil to engage with its hammer releasable end.
 4. An automatically-selective single-trigger firing mechanism for a double-barrelled firearm, comprising: a receiver with a breech end; a pair of hammers disposed side-by-side in said receiver and pivotally mounted for forward movement toward said breech end; biasing means urging each hammer into forward movement; a pair of elongated sears each having a forward hammer-engageable end and a hammer releasable end, said sears pivotally mounted closely adjacent each other within the receiver; biasing means urging each sear into engaging its respective hammer in a cocked position against forward movement until the sear pivots to release it; a trigger operative between a pulled and rest position having an upper elongated base comprising a forward end and a rearward end, said trigger pivotally mounted to said receiver between the ends of the base; biasing means to urge the trigger towards the rest position from said pulled position; an elongated upstanding connector arm articulatively attached at one end thereof to the forward end of said trigger base, and engageable at the other end thereof with the rearward end of either of the two sears when said hammers are in the cocked position; said connector arm further comprising a first sear engageable step at its sear-engageable end, and to the rear on either side of said first step, a second sear-engageable step; selector means for positioning the first step of the connector arm upon either one of said sears when both hammers are cocked; mechanical biasing means for urging the connector arm forward to engage the selected sear upon its first step and subsequent to that, a pivoting of the engaged sear will cause said connector arm to move further forward to engage the other sear upon said second step after the trigger fully returns from its pulled to its rest position, and after recoil and counter-recoil cycles have terminated; a second elongated upstanding connector arm articulatively attached at its lower end thereof to the rearward end of said trigger base; and an elongated selector block positioned above the trigger base and pivotally connected to the forward connector arm at its sear engageable end, and the second connector arm to form a four-bar linkage assembly.
 5. An automatically-selective single-trigger firing mechanism for a double-barrelled firearm comprising: a receiver housing with a breech end; a pair of hammers disposed side-by-side in said housing and pivotally mounted for forward movement toward said breech end; biasing means urging each hammer into forward movement; a pair of elongated sears each having a forward hammer-engageable end and a hammer releasable end, said sears pivotally mounted closely adjacent each other within the receiver housing; biasing means urging each sear into engaging its respective hammer in a cocked position against forward movement until the sear pivots to release it; a trigger operative between a pulled and rest position having an upper elongated base comprising a forward end and a rearward end, said trigger pivotally mounted to said receiver housing between the ends of the base; biasing means to urge the trigger towards the rest position from said pulled position; an elongated upstanding connector arm articulatively attached at one end thereof to the forward end of said Trigger base, and engageable at the other end thereof with the rearward end of either of the two sears when said hammers are in the cocked position; said connector arm further comprising a first sear engageable step at its sear-engageable end, and to the rear on either side of said first step, a second sear-engageable step; selector means for positioning the first step of the connector arm upon either one of said sears when both hammers are cocked; mechanical biasing means for urging the connector arm forward to engage the selected sear upon its first step and subsequent to that, a pivoting of the engaged sear will cause said connector arm to move further forward to engage the other sear upon said second step after the trigger fully returns from its pulled to its rest position, and after recoil and counter-recoil cycles have terminated; said selector means to position the first step of the connector arm upon one of the sears comprising: a selector lever pivotally connected at a forward end thereof to the receiver housing, with a rearward end pivotably arcuate about said forward end from a first selective position to a second selective position, and having a neutral position between said selective positions; and a toggle mechanism connected to the selector lever and the connector arm, and operatively constructed to transform the arcuate movement of the selector lever into laterally moving the connector arm to a position capable of engaging the respective sears.
 6. The automatically selective firing mechanism of claim 5, wherein the toggle mechanism comprises: a toggle block disposed within the housing and rigidly connected at a forward end thereof to the forward end of said selector lever, said toggle block having a rearward end free to pivot about its forward end, whereby the toggle block motion will substantially conform to the motion prescribed to said lever; an elongated selector block having a prolongated slot and an abutment for engagement with a toggle stud, said selector block attached to the connector arm and restrained to move with said connector arm within the housing; and an elongated toggle link pivotally attached at one end thereof to the free pivoting end of said toggle block, and having its other end restrained for sliding forward and backward within the receiver housing by a toggle stud extending upwardly into a slot in the wall of the receiver housing, said stud also extending downwardly from said slide to engage the selector block abutment against forward movement when the selector lever is in the neutral position so as to prevent the connector arm from engaging the respective sears.
 7. The automatically selective firing mechanism of claim 6, wherein the toggle mechanism further comprises: a toggle guide pin attached to said toggle block between its forward and rearward ends and extending downwardly from said toggle block to protrude into the prolongated slot of the selector block, whereby the arcuate movement of the selector lever to either its first or second position will cause the toggle guide pin to move laterally within the receiver housing and force the selector block to move to a position capable of engaging the respective sears.
 8. An automatically-selective single trigger firing mechanism for a double-barrelled firearm comprising: a receiver housing; a pair of hammers pivotally mounted in said housing to move from a rear, cocked position to a forward, uncocked position; biasing means urging each of said hammers forwardly; a pair of sears pivotally mounted rearwardly of said hammers, each of which selectively engages and retains a corresponding hammer in the cocked position; a four-bar linkage system positioned rearwardly of said pair of sears, and means pivotally mounting said linkage system to said receiver housing so as to be movable forwardly and rearwardly as well as laterally thereof; sear engaging means on said linkage system for selectively engaging a predetermined one of said pair of sears, and after firing of the first barrel, to automatically engage the other of said pair of sears; biasing means urging said linkage system forwardly into sear engaging position; selector means on said receiver housing connected to said linkage system for laterally moving said linkage system and the sear engaging means thereon to selectively position the sear engaging means on to the desired sear; and a trigger on said linkage system so that upon pulling said trigger rearwardly, the linkage system is caused to be pivoted forwardly and downwardly to depress the selected sear and release the corresponding hammer, thus permitting the firearm to fire.
 9. An automatically-selective single-trigger firing mechanism as recited in claim 8 wherein said four-bar linkage system comprises an elongated trigger base, upstanding forward and rear connector arms having their lower ends articulatively connected to the forward and rear ends respectively of said elongated trigger base, and an elongated selector block positioned above said trigger base and pivotally connected to the upper ends of said forward and rear connector arms respectively.
 10. An automatically-selective single trigger firing mechanism for a double-barrelled firearm as recited in claim 9 wherein slot means are provided in said trigger base in order to receive the lower ends of said forward and rear connector arms, each of said lower ends of said connector arms having an enlarged and radiused portion with a maximum thickness which is slightly less than the width of said slot means, an opening through each of said enlarged portions through which pivot pins are inserted to mount said connector arms to said trigger base, said openings being angularly relieved at each end of said openings to permit lateral movement of said connector arms relative to said pivot pins. 